1. Field of the Invention
The present invention relates to a .gamma.-dicalcium silicate-containing cement composition. More particularly, the present invention relates to a .gamma.-dicalcium silicate-containing cement composition, an aqueous cement mixture containing the cement composition, and a hardened cement material prepared from the aqueous cement mixture and having enhanced flexural strength, water resistance, and heat resistance.
2. Description of the Prior Art
Conventional cement products obtained by hydraulically hardening conventional cement compositions do not always exhibit high flexural strength. That is, when conventional products are produced from conventional cement compositions, wherein the cement particles have a usual size at a usual water/cement ratio, the products exhibit flexural strength of a level of approximately 5 to 10 MPa.
It is known that the flexural strength of cement products can be increased by mixing a fiber material into the cement composition. However, even if fiber material is added, it is difficult to attain a flexural strength of the resultant cement products exceeding 40 MPa. Addition of the fiber material also results in decreased fluidity and moldability of the cement composition.
Other approaches to enhance the flexural strength of cement products have been to control the size and amount of pores formed in the cement products or to regulate the viscosity conditions of the cement composition. However, it is known that while cement products prepared in accordance with the above-mentioned methods have enhanced flexural strength, they are unsatisfactory in flame resistance (heat resistance and fire resistance) and water resistance and, therefore, are useless in practice.
In addition, since conventional cement compositions contain, as a major component, Portland cement or another hydraulic cement, the resultant cement products are undesirably discolored gray and, therefore, have a poor appearance.